Abstract

We report theory and experimental results for a new class of phenomena in condensed matter optics when strong optical fields ∼0.1-5 V/Å radically change the both energies and wave functions of electronic states on time scale of ∼1 fs, i.e., within an optical period. Such fields, if adiabatic, cause phenomena such as the Wannier-Stark localization, formation of quantum bouncers at the surfaces, and anticrossings of adiabatic levels causing metallization of the dielectric. Fast optical fields by their instantaneous magnitude, not average envelope, drive currents in dielectrics and control their properties, including optical absorption and reflection, and extreme UV absorption in a non-perturbative manner. Such a control can be deep but non-damaging if the excitation pulse is short enough (∼1-2 oscillations) and its instantaneous field is controlled to be < 2.5 V/Å. This offers potential for petahertz-bandwidth signal processing.